Answer:
Step-by-step explanation:
I suspect that you actually meant C = 2π r, the formula for the circumference of a circle.
But if your C=2vpi r is correct, then dividing both sides of this equation by 2v*pi yields the desired equation:
C
r = ---------------
2v*pi
18,36,54,72,90 are first five multiples of 18
thanks thanks thanks thanks thanks for your points
Answer: 256 units squared
So basically you times 4*4*2*8.